After nearly 8 months of pre-production, principal photography on "Multiplicity" began in late August, 1995. The film followed a 98-day production schedule, much longer than the average shooting schedule in order to accommodate the demands of visual effects filming. At the height of the production, Keaton could find himself playing four characters faced with the rigors of hair, make-up and wardrobe changes for each character before even beginning to create on-screen performances and deal with the technical challenges of visual effects filming. Make-up artist Bob Mills, hairstylist Marlene Williams and costume designer Shay Cunliffe all assisted Keaton in physically transforming into each of the clones.

"I wanted each of the clones clothes to be different and yet to have some Dougness to them," explains Cunliffe. "Doug is your average American guy in plaid shirt and jeans. It was taking that and putting it in a slightly different context for each of the clones. So Two wears much rougher clothing while Three's plaid shirts are much prettier and pressed." Cunliffe says she took inspiration from her seven year-old son in designing Four's wardrobe. "The transformation into each character could happen anywhere," jokes Keaton, "but it usually begins somewhere in make-up."

While in make-up, Keaton also worked with dialogue coach Diane Gnagnarelli perfecting annunciation and defining mannerisms for each of the clones. He might begin the day looking his tidiest as spit and polished Three before moving to Doug. For Two, beard stubble would be applied for that ultra-masculine look before slipping into his muddied work boots and t-shirt, and Four, a true original, usually appeared last.